feat: add solution 2200. Find All K-Distant Indices in an Array

Author: tzuyi0817

solutions/2200. Find All K-Distant Indices in an Array/README.md

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+# [2200. Find All K-Distant Indices in an Array](https://leetcode.com/problems/find-all-k-distant-indices-in-an-array)
+
+## Description
+
+<div class="elfjS" data-track-load="description_content"><p>You are given a <strong>0-indexed</strong> integer array <code>nums</code> and two integers <code>key</code> and <code>k</code>. A <strong>k-distant index</strong> is an index <code>i</code> of <code>nums</code> for which there exists at least one index <code>j</code> such that <code>|i - j| &lt;= k</code> and <code>nums[j] == key</code>.</p>
+
+<p>Return <em>a list of all k-distant indices sorted in <strong>increasing order</strong></em>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre><strong>Input:</strong> nums = [3,4,9,1,3,9,5], key = 9, k = 1
+<strong>Output:</strong> [1,2,3,4,5,6]
+<strong>Explanation:</strong> Here, <code>nums[2] == key</code> and <code>nums[5] == key.
+- For index 0, |0 - 2| &gt; k and |0 - 5| &gt; k, so there is no j</code> where <code>|0 - j| &lt;= k</code> and <code>nums[j] == key. Thus, 0 is not a k-distant index.
+- For index 1, |1 - 2| &lt;= k and nums[2] == key, so 1 is a k-distant index.
+- For index 2, |2 - 2| &lt;= k and nums[2] == key, so 2 is a k-distant index.
+- For index 3, |3 - 2| &lt;= k and nums[2] == key, so 3 is a k-distant index.
+- For index 4, |4 - 5| &lt;= k and nums[5] == key, so 4 is a k-distant index.
+- For index 5, |5 - 5| &lt;= k and nums[5] == key, so 5 is a k-distant index.
+- For index 6, |6 - 5| &lt;= k and nums[5] == key, so 6 is a k-distant index.
+</code>Thus, we return [1,2,3,4,5,6] which is sorted in increasing order. 
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre><strong>Input:</strong> nums = [2,2,2,2,2], key = 2, k = 2
+<strong>Output:</strong> [0,1,2,3,4]
+<strong>Explanation:</strong> For all indices i in nums, there exists some index j such that |i - j| &lt;= k and nums[j] == key, so every index is a k-distant index. 
+Hence, we return [0,1,2,3,4].
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums.length &lt;= 1000</code></li>
+	<li><code>1 &lt;= nums[i] &lt;= 1000</code></li>
+	<li><code>key</code> is an integer from the array <code>nums</code>.</li>
+	<li><code>1 &lt;= k &lt;= nums.length</code></li>
+</ul>
+</div>
+
+<p>&nbsp;</p>
+
+## Solutions
+
+**Solution: `Two Pointers`**
+
+- Time complexity: <em>O(n)</em>
+- Space complexity: <em>O(n)</em>
+
+<p>&nbsp;</p>
+
+### **JavaScript**
+
+```js
+/**
+ * @param {number[]} nums
+ * @param {number} key
+ * @param {number} k
+ * @return {number[]}
+ */
+const findKDistantIndices = function (nums, key, k) {
+  const n = nums.length;
+  const result = [];
+  let right = 0;
+
+  for (let index = 0; index < n; index++) {
+    while (right < n && (nums[right] !== key || right < index - k)) {
+      right += 1;
+    }
+
+    if (right === n) return result;
+
+    if (Math.abs(index - right) <= k) {
+      result.push(index);
+    }
+  }
+
+  return result;
+};
+```

solutions/2200. Find All K-Distant Indices in an Array/solution.js

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+/**
+ * @param {number[]} nums
+ * @param {number} key
+ * @param {number} k
+ * @return {number[]}
+ */
+const findKDistantIndices = function (nums, key, k) {
+  const n = nums.length;
+  const result = [];
+  let right = 0;
+
+  for (let index = 0; index < n; index++) {
+    while (right < n && (nums[right] !== key || right < index - k)) {
+      right += 1;
+    }
+
+    if (right === n) return result;
+
+    if (Math.abs(index - right) <= k) {
+      result.push(index);
+    }
+  }
+
+  return result;
+};